System and method of capturing geothermal heat from within a drilled well to generate electricity

ABSTRACT

A closed-loop, solid-state system generates electricity from geothermal heat from a well by flow of heat, without needing large quantities of water to conduct heat from the ground. The present invention contemplates uses for depleted oil or gas wells and newly drilled wells to generate electricity in an environmentally-friendly method. Geothermal heat is conducted from the Earth to a heat exchanging element to heat the contents of pipes. The pipes are insulated between the bottom of the well and the surface to minimize heat dissipation as the heated contents of the pipes travel to the surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/131,967, filed on Jun. 13, 2008, the contents of which are herebyincorporated in their entirety.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of convertinggeothermal energy into electricity. More specifically, the presentinvention relates to capturing geothermal heat from deep within adrilled well and bringing this geothermal heat to the Earth's surface togenerate electricity in an environmentally friendly process.

Wells that have been drilled for oil and gas exploration that are eitherdepleted, or have never produced oil or gas, usually remain abandonedand/or unused and may eventually be filled. Such wells were created at alarge cost and create an environmental issue when no longer needed fortheir initial use.

Wells may also be drilled specifically to produce heat. While there areknown geothermal heat/electrical methods and systems for using thegeothermal heat/energy from deep within a well (in order to produce aheated fluid (liquid or gas) and generate electricity therefrom), thesemethods have significant environmental drawbacks and are usuallyinefficient in oil and gas wells due to the depth of such wells.

More specifically, geothermal heat pump (GHP) systems and enhancedgeothermal systems (EGS) are well known systems in the prior art forrecovering energy from the Earth. In GHP systems, geothermal heat fromthe Earth is used to heat a fluid, such as water, which is then used forheating and cooling. The fluid, usually water, is actually heated to apoint where it is converted into steam in a process called flash steamconversion, which is then used to generate electricity. These systemsuse existing or man made water reservoirs to carry the heat from deepwells to the surface. The water used for these systems is extremelyharmful to the environment, as it is full of minerals, is caustic andcan pollute water aquifers. Such deep-well implementations require thata brine reservoir exists or that a reservoir is built by injecting hugequantities of water into an injection well, effectively requiring theuse of at least two wells. Both methods require that polluted dirtywater is brought to the surface. In the case of EGS systems, waterinjected into a well permeates the Earth as it travels over rock andother material under the Earth's surface, becoming polluted, caustic,and dangerous.

A water-based system for generating heat from a well presentssignificant and specific issues. For example, extremely large quantitiesof water are often injected into a well. This water is heated and flowsaround the inside of the well to become heated and is then extractedfrom the well to generate electricity. This water becomes polluted withminerals and other harmful substances, often is very caustic, and causesproblems such as seismic instability and disturbance of naturalhydrothermal manifestations. Additionally, there is a high potential forpollution of surrounding aquifers. This polluted water causes additionalproblems, such as depositing minerals and severely scaling pipes.

Geothermal energy is present everywhere beneath the Earth's surface. Ingeneral, the temperature of the Earth increases with increasing depth,from 400°-1800° F. at the base of the Earth's crust to an estimatedtemperature of 6300°-8100° F. at the center of the Earth. However, inorder to be useful as a source of energy, it must be accessible todrilled wells. This increases the cost of drilling associated withgeothermal systems, and the cost increases with increasing depth.

In a conventional geothermal system, such as for example and enhancedgeothermal system (EGS), water or a fluid (a liquid or gas), is pumpedinto a well using a pump and piping system. The water then travels overhot rock to a production well and the hot, dirty water or fluid istransferred to the surface to generate electricity.

As mentioned earlier herein, the fluid (water) may actually be heated tothe point where it is converted into gas/steam. The heated fluid orgas/steam then travels to the surface up and out of the well. When itreaches the surface, the heated water and/or the gas/steam is used topower a thermal engine (electric turbine and generator) which convertsthe thermal energy from the heated water or gas/steam into electricity.

This type of conventional geothermal system is highly inefficient invery deep wells for several of reasons. First, in order to generate aheated fluid required to efficiently operate several thermal engines(electric turbines and generators), the fluid must be heated to degreesof anywhere between 190° F. and 1000° F. Therefore the fluid must obtainheat from the surrounding hot rock. As it picks up heat it also picks upminerals, salt, and acidity, causing it to very caustic. In order toreach such desired temperatures in areas that lack a shallow-depthgeothermal heat source (i.e. in order to heat the fluid to this desiredtemperature), the well used must be very deep. In this type of prior artsystem, the geologies that can be used because of the need for largequantities of water are very limited.

The deeper the well, the more challenging it is to implement awater-based system. Moreover, as the well becomes deeper the gas orfluid must travel further to reach the surface, allowing more heat todissipate. Therefore, using conventional geothermalelectricity-generating systems can be highly inefficient because longlengths between the bottom of a well and the surface results in the lossof heat more quickly. This heat loss impacts the efficacy and economicsof generating electricity from these types of systems. Even more wateris required in such deep wells, making geothermal electricity-generatingsystems challenging in deep wells.

Accordingly, prior art geothermal systems include a pump, a pipingsystem buried in the ground, an above ground heat transfer device andtremendous quantities of water that circulates through the Earth to pickup heat from the Earth's hot rock. The ground is used as a heat sourceto heat the circulating water. An important factor in determining thefeasibility of such a prior art geothermal system is the depth ofwellbore, which affects the drilling costs, the cost of the pipe and thesize of the pump. If the wellbore has to be drilled to too great adepth, a water-based geothermal system may not be a practicalalternative energy source. Furthermore, these water-based systems oftenfail due to a lack of permeability of hot rock within the Earth, aswater injected into the well never reaches the production well thatretrieves the water.

BRIEF SUMMARY OF THE INVENTION

The present invention discloses, generally, a system and method ofeconomically conducting geothermal heat from a well to the Earth'ssurface and then using this heat to generate electricity in aclosed-loop, solid state system. This system and method, known asGTherm, is environmentally responsible because there is no fluid flowfrom the Earth. It is entirely based on heat flow from rock deep withina well through solid materials to heat contents of pipes pumped in aclosed loop from and to the Earth's surface.

The present invention discloses a system for generating electricityusing geothermal heat from within a drilled well, comprising a heatharnessing component having a closed-loop solid state heat extractionsystem. The closed-loop solid state heat extraction system includes aheat exchanging element positioned within a heat nest in a well and aheat conductive material inserted into the well to conduct geothermalheat from the rock surrounding the heat nest to the heat exchangingelement. The rock surrounding the heat nest heats the heat conductivematerial to an equilibrium temperature determined by a surface area ofthe rock surrounding the heat nest, the equilibrium temperature being atemperature at which the rock surrounding the heat nest and generatingthe geothermal heat continually recoups the geothermal heat it isconducting to the heat conductive material and above which thegeothermal heat generated by the rock surrounding the heat nestdissipates as the heat conductive material conducts heat from the rocksurrounding the heat nest to the heat exchanging element. The systemalso includes an electricity generating component that includes athermal engine, the electricity generating component receivinggeothermal heat from contents of a piping component coupling the heatharnessing component to the electricity generating component, the pipingcomponent including a set of downward-flowing pipes and a set ofupward-flowing pipes, the upward-flowing pipes conveying contents of thepiping component heated by the heat exchanging element to a surface ofthe well and into the electricity generating component. The systemfurther includes insulation inserted into the well and substantiallysurrounding at least the upward-flowing pipes at least one positionbetween the heat nest and the surface of the well to maintain atemperature of the contents of the piping system substantially constantas the contents of the piping system are pumped to the surface of thewell. The closed-loop, solid state heat extraction system extractsgeothermal heat from the well without exposing the rock surrounding theheat nest to a liquid flow.

In another embodiment, the present invention discloses a heat extractionsystem for generating geothermal heat from within a drilled well. Theheat extraction system comprises a heat conductive material injectedinto an area within a heat nest near a bottom of a drilled well betweena heat exchanging element and rock surrounding the heat nest to form aclosed-loop, solid state heat exchange to heat contents of a pipingsystem flowing into and out of the heat exchanging element at anequilibrium temperature at which the rock surrounding the heat nest andgenerating the geothermal heat continually recoups the geothermal heatit is conducting to the heat conductive material and above which thegeothermal heat generated by the rock surrounding the heat nestdissipates as the heat conductive material conducts heat from the rocksurrounding the heat nest to the heat exchanging element. The heatconductive material solidifies to substantially fill the area within theheat nest to transfer heat from the rock surrounding the heat nest andthe heat exchanging element, the piping system bringing the contents ofthe piping system from a surface of the well into the heat nest andcarrying heated contents to the surface of the well from the heat nest.The closed-loop solid state heat extraction system extracts geothermalheat from the well without exposing the rock surrounding the heat nestto a liquid flow.

In another embodiment, the present invention discloses a method ofgenerating electricity using geothermal heat from within a drilled well.The method comprises extracting geothermal heat from rock surrounding aheat nest positioned at a location within a well by injecting a heatconductive material into the heat nest to surround a heat exchangingelement to form a closed-loop, solid-state heat extraction system, theheat conductive material exchanging geothermal heat from the rocksurrounding the heat nest to the heat exchanging element to heatcontents of a piping system, the contents heated within the heat nest atan equilibrium temperature at which the rock surrounding the heat nestand generating the geothermal heat continually recoups the geothermalheat it is exchanging with the heat conductive material and above whichthe geothermal heat generated by the rock surrounding the heat nestdissipates as the heat conductive material exchanges heat from the rocksurrounding the heat nest to the heat exchanging element. The methodalso comprises insulating the piping system at least one point betweenthe heat nest and the surface of the well to maintain a temperature ofthe contents of the piping system substantially constant as the contentsof the piping system are pumped to the surface of the well. The methodfurther comprises pumping the heated contents of the piping system intoan electricity generating component after the heated contents of thepiping system reaches the surface of the well. The closed-loop solidstate heat extraction system extracts geothermal heat from the wellwithout exposing the rock surrounding the heat nest to a liquid flow.

In still another embodiment, the present invention discloses a method ofextracting geothermal heat from within a drilled well. The methodcomprises determining a type of rock at a depth of a well, a surfacearea of the rock at the depth of the well, and a heat conductivityfactor of the rock at the depth of the well, increasing the surface areaof the rock at a desired point in the well between a heat point of thewell and a bottom of the well, and forming a heat nest within the wellbeginning at the bottom of the well and ending at the heat point of thewell. The method also includes injecting a heat conductive materialbetween rock surrounding the heat nest and a heat exchanging elementwithin the heat nest to form a closed-loop, solid-state heat extractionsystem to exchange heat from the rock surrounding the heat nest to theheat exchanging element to heat a contents of a piping system flowinginto and out of the heat exchanging element at an equilibriumtemperature at which the rock surrounding the heat nest and generatingthe geothermal heat continually recoups the geothermal heat it isexchanging with the heat conductive material and above which thegeothermal heat generated by the rock surrounding the heat nestdissipates as the heat conductive material exchanges heat from the rocksurrounding the heat nest to the heat exchanging element. The methodfurther comprises insulating the piping system between the heat nest anda surface of the well. The closed-loop solid state heat extractionsystem extracts geothermal heat from the well without exposing the rocksurrounding the heat nest to a liquid flow.

Other embodiments, features and advantages of the present invention willbecome more apparent from the following description of the embodiments,taken together with the accompanying several views of the drawings,which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a block view of a system according to one embodiment of thepresent invention showing a closed loop system having pipes, a heatharnessing component, and an electricity generating component;

FIG. 2 is a close-up view of a heat exchanging element according toembodiment of the present invention;

FIG. 3 is a cross-sectional view pipes in a bore hole of a wellaccording to one embodiment of the present invention;

FIG. 4 is a flow chart showing steps in a method for generatingelectricity according to one embodiment of the present invention;

FIG. 5 is a cross-sectional view of a well and heat nest according toone embodiment of the present invention; and

FIG. 6 is a cross-sectional view of a heat-exchanging element accordingto one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description of the present invention reference is madeto the accompanying drawings which form a part thereof, and in which isshown, by way of illustration, exemplary embodiments illustrating theprinciples of the present invention and how it may be practiced. It isto be understood that other embodiments may be utilized to practice thepresent invention and structural and functional changes may be madethereto without departing from the scope of the present invention.

The present invention economically and efficiently conducts geothermalheat from deep within a well to the surface of the Earth, and then usesthis geothermal heat to generate electricity in a closed-loop,solid-state system. This closed-loop, solid-state system generateselectricity by heat flow rather than by water flow, so that it does notrequire large quantities of water separately injected into the well.

Referring to FIG. 1, the present invention includes a heat harnessingcomponent 10 and an electricity generating component 20. As shown inFIG. 1, the heat harnessing component includes a heat exchanging element40, and a heat conductive material 100 that transfers geothermal heatfrom hot rock near a bottom 90 of the well 110 to the heat exchangingelement 40. The present invention also includes a piping system 50,comprised of one or more downward-flowing pipes 60 and one or moreupward-flowing pipes 80. The piping system's 50 contents, pumped fromand to the surface by a pumping mechanism 30, includes a heat conductivefluid or gas that flows through the closed-loop system and carries heatto the surface of the well 110. The electricity generating component 20includes a thermal engine 120 which converts heat into electricalenergy. The thermal engine 120 may include an electric turbine and agenerator. The piping system 50 couples the heat harnessing component 10and the electricity generating component 20 together.

The downward-flowing pipes 60 and the upward-flowing insulated pipes 80of the piping system 50 may be insulated with insulation 70. Thediameter of the downward-flowing pipes 60 and the upward-flowinginsulated pipes 80 used in the piping system 50 may vary, and should bedetermined in accordance with the specific flow requirements desired. Inanother embodiment, the downward flowing insulated pipes 60 and theupward flowing insulated pipes 80 are integrated into a single element,to the fullest extent possible, in order to simplify installation.

In another embodiment, the one or more downward-flowing pipes 60 and theone or more upward-flowing insulated pipes 80 are made of a flexiblematerial and can be spooled into the well. The piping system 50 istherefore flexible and comprised of several different layers of woundcorrosion resistant steel wiring and leak-proof thermoplastic polymerssuch as polyethylene, polyamide 11, and/or PVD. The number of layersused in any one particular pipe in the piping system 50 will bedetermined as a function of the depth of the well andpressure/temperature requirements.

Utilizing the pumping mechanism 30 and the piping system 50, contents ofthe piping system 50, which may be a heat conductive fluid comprised ofliquid or gas, is piped downward through the one or more downwardflowing pipes 60 and into the well 110. The contents are pumped downwardthrough the one or more downward pipes 60 to a level of the well 110where there is significant geothermal heat that is sufficient to heatthe contents. This lowest depth where the first appropriate heat isencountered will be referred to hereinafter as the heat point 130,although it is understood that there is geothermal heat at many levelsand this geothermal heat becomes greater as the depth of the well 110increases. The area between the heat point 130 and the bottom 90 of thewell 110 is called the heat nest 140.

The heat exchanging element 40 is positioned in the heat nest 140 at apoint between the heat point 130 of the well and the bottom 90 of thewell 110. The downward-flowing pipes 60 are coupled to this heatexchanging element 40 on a first side 150, allowing the contents to passthrough the heat exchanging element 40 on the first side 150 of the heatexchanging element 40. The heat exchanging element 40 draws geothermalheat from the Earth using the heat conducting material 100 whichinterfaces with the hot rock surrounding the heat nest 140 and uses thisgeothermal heat to heat the contents as they pass through the heatexchanging element 40. Unlike conventional systems which will simplydraw a heated fluid from a well to the top surface, and then utilize aheating element in order to further heat the fluid at the surface level,the present invention has its heat exchanging element 40 actuallycontained deep within the well 110 itself. The heat exchanging element40 and the heat conductive material 100 form a closed-loop, solid stateextraction system in which heat flows rather than water. Thisclosed-loop, solid state extraction system has no negative environmentalimpacts and only requires the presence of hot rock.

The heat nest 140 is constructed at a desired depth after a surface areaof the surrounding rock has been increased to ensure maximum temperatureand flow of geothermal heat generated by the rock. A variety oftechniques, discussed herein, may be employed to increase surface areaof the rock. Increasing the surface area of the rock ensures a steady,continual equilibrium temperature and maximum flow of geothermal heatfrom the surrounding rock and into the heat conductive material 100,which is injected after the heat nest 140 is constructed. Therefore, itis an objective of the present invention to increase the surface area ofthe rock surrounding the to-be-built heat nest 140 as much as possible,as doing so improves heat flow from the rock to the heat conductivematerial 100 to the heat exchanging element 40 to the contents of thepiping system 50.

One method of increasing the surface area of the rock is by fracturingthe rock surrounding the heat nest to create cracks and crevices thatexpand the surface area. The present invention contemplates that manyways of fracturing the rock may be used, including throughhydro-fracting, through drilling bore holes in multiple directions asdescribed herein, and generally any current or future method of breakingor fracturing rock deep under the Earth's surface.

Accordingly, the equilibrium temperature is the temperature, or range oftemperatures in one embodiment, in the system and method of the presentinvention at which geothermal heat heating the contents of the pipingsystem 50 equals the rate at which the hot rock supplying the geothermalheat recoups, or re-generates, the heat it is transferring out. Ifgeothermal heat is transferred out above the equilibrium temperature,geothermal heat in the hot rock will be depleted or dissipated, and rateand temperature of the heat extraction deteriorates. If geothermal heatis transferred out at or below the equilibrium temperature, the rate ofheat extraction will be continual and steady, therefore a steady stateheat extraction system is achieved.

Heat exchanging elements generally are devices built for efficient heattransfer which typically transfer heat from one fluid to another. Suchheat exchanging elements therefore feature a fluid flow in which fluidflows through two sides of the heat exchanging element, with one fluidheating the other. They are widely used in many engineering processes.Some examples include intercoolers, pre-heaters, boilers and condensersin power plants.

FIG. 2 is a diagram showing the heat exchanging element 40 utilized inthe present invention. A heat exchanging element 40 of the present heatsfluid within the closed-loop, steady state heat extraction systemaccording to the present invention by a heat flow, rather than a fluidflow. By applying the first law of thermodynamics to a heat exchangingelement working at steady-state condition, we obtain:μχ=0where,

μ=mass flow of the i-th fluid

χ=change of specific enthalpy of the i-th fluid

Referring to FIG. 2, the heat exchanging element 40 is shown as across-flow heat exchanger in which heat flows perpendicular to the fluidwhich needs to be heated, such that the heat flow 240 passes over/aroundthe exchanger in a perpendicular direction, thereby heating the fluid230 which flows through from a direction perpendicular to the heat flow240.

In one embodiment, the heat exchanging element 40 of the presentinvention is a high-temperature heat exchanger (“HTHE”) comprised of arecuperative type “cross flow” heat exchanger, in which fluids exchangeheat on either side of a dividing wall. Alternatively, the heatexchanging element 40 may be comprised of an HTHE which utilizes aregenerative and/or evaporative design. Regardless of the configurationof heat exchanging element used, the present invention contemplates thatfluid passing through the heat exchanging element 40 is heated by a heatflow generated by extracting geothermal heat from rock surrounding theheat nest 140, rather than a flow of more than one fluid.

In another embodiment, the heat exchanging element 40 includes aplurality of smaller capillaries 170. The contents enter the heatexchanging element 40 from the one or more downward-flowing pipes 60,where it is then dispersed, flowing through each of the plurality ofsmaller capillaries 170. The capillaries 170 may be thinner than the oneor more downward-flowing pipes 60. For example, the plurality ofcapillaries 170 may have a smaller diameter than the one or moredownward-flowing pipes 60, thereby allowing the contents to heat morequickly as it passes through the capillaries 170—and thereby increasingthe overall efficacy of the heat exchanging element 40. In anotherembodiment, the combined flow of the capillaries 170 of the heatexchanging element 40 must be able to accommodate an equal or greaterflow than the one or more downward-flowing pipes 60 and the one or moreupward-flowing pipes 80.

In yet another embodiment, the heat exchanging element 40 may becomprised of a titanium clad tubesheet, wherein the tubesheet may beformed from a high temperature nickel based alloy or ferritic steel. Inthis way, the heat exchanging element 40 is able to operate efficientlyunder high temperature/pressure conditions. Moreover, the thickness ofthe titanium may vary in accordance with specific temperature and/orpressure conditions under which the heat exchanging element 40 operates.

It is understood that there are other types of heat exchanging elements40 known in the art which may also be used in the present invention.Examples include but are not limited to parallel heat exchangers and/orreverse flow heat exchangers. In alternative embodiments, any of thesetypes of exchangers may be utilized. A primary consideration indesigning the heat exchanging element 40 will be to ensure its efficientoperation under high temperature/pressure conditions. Further, any suchheat exchanging element 40 utilized in the present invention must besized to fit within the bore hole 190 of the well 110.

Additionally, the internal components of the heat exchanging element 40may include different forms designed to maximize the amount of heattransferred into the piping system 50 within the heat exchanging element40 to heat the contents as much as possible.

Still referring to FIG. 1, the one or more upward-flowing pipes 80 ofthe piping system 50 are coupled to the heat exchanging element 40 on ansecond, opposing side 160 of the heat exchanging element 40. The one ormore upward-flowing pipes 80 draw the heated contents from the heatexchanging element 40 and bring the heated contents upward from the heatpoint 130 in the well 110 to the top 180, or surface. The bore hole 190from the heat point 130 to the top 180 of the well 110 is completelyinsulated to prevent heat loss. The heat exchanging element 40 and thepiping system 50 form a closed loop that separates the contents from theenvironment creating a completely environmentally-friendly system.

In one embodiment, the fluid that needs to be heated (or, also usedherein, the contents of the piping system 50) should be optimized tocarry heat. An example of such a fluid is antifreeze used inautomobiles. Gas or water can also be used as a fluid. Further, thefluid should not have any corrosive properties, and the material used toconstruct the piping system 50 needs to be resistant to the fluid.Moreover, the fluid is pressurized within the piping system 50 so thesystem should be able to withstand pressure generated by the depth ofthe well 110 and the pumping mechanism 30, as the fluid is pumpedthrough the system. The fluid used is environmentally inert and causesno environmental issues should the piping system 50 break.

Referring still to FIG. 1 and construction of a system according to thepresent invention, once the piping system 50 and heat exchanging element40 are fully installed in the well 110, the heat nest 140 is completelyfilled with the heat conductive material 100. Once the heat conductivematerial 100 fills the heat nest 140, the rest of the bore hole of thewell 110 is filled with insulation 70. The heat conductive material 110must have heat conductive properties and allow it to bond and solidifywithin the heat nest 140. The heat conductive material 100 is designedto retain and conduct heat efficiently, maintaining a substantiallyconstant temperature throughout the heat nest 140. The heat conductivematerial 100 connects the hot rock surrounding the heat nest 140 to theheat exchanging element 40, creating the heat harnessing component 10.

The heat conductive material 100 used in the present invention may takemany forms. Generally, any substance or material that conducts heat atthe temperatures required within a well 110 may be used. Examples ofsuch substances or material include but are not limited to grout,enhanced grout, plastic, ceramics, enhanced ceramics, molten metal suchas for example copper, or any combination of these.

Additionally, the present invention contemplates that one or moreadditional materials may also be injected into a well 110 (via a pipesuch as large diameter pipe 210) and may be used to capture and conductgeothermal heat generated from surface area of the rock. Examples ofsuch additional material include, but are not limited to, ball bearings,beads, wire or metallic mesh, and pipes. Such additional materialincreases the conduction of the geothermal heat by filling cracks andcrevices in the rock surrounding the heat nest. By expanding the surfacearea of the rock surrounding heat nest 140 and using the additionalmaterial, you therefore expand the capacity of the heat conductivematerial 100. The additional material itself increases the surface areaof conduction, meaning that geothermal heat conducted from the rocksurrounding the heat nest 140 is released over greater surface areasprovide by the introduction of the additional materials into the heatnest 140. The heat conductive material 100, injected into the heat nest140 via the large diameter pipe 210, also fills these cracks andcrevices around the additional material and solidifies, adding to theconduction capabilities by way of increased surface area. Thus, the heatconductive material 100 may be used in conjunction with such additionalmaterial to take advantage of increases in the surface area of the rocksurrounding the heat nest 140.

The present invention also contemplates, in another embodiment, thatsuch additional materials could be used without heat conductive material100. Additional materials as described herein also conduct geothermalheat from rock surrounding the heat nest to the heat exchanging element40. In an embodiment where the heat conductive material 100 is usedtogether with the additional materials as described here, the heatconductive material 100 bonds with the additional materials andsolidifies around them.

The present invention also contemplates that the system may furtherinclude the equilibrium temperature being increased by increasing thesurface area of the rock surrounding the heat nest; at least oneadditional bore hole being drilled into the rock to increase the surfacearea of the rock; and at least one additional material being injectedinto the heat nest, wherein the at least one additional material is aheat rod.

FIG. 3 illustrates a cross-sectional diagram for a well 110 in which thesystem of the present invention is utilized. The bore hole 190 of thewell 110 has positioned therein the one or more upward-flowing pipes 60and the one or more downward-flowing pipes 80. A space between the wall200 of the bore hole 190 and the one or more downward-flowing pipes 60and the one or more upward-flowing pipes 80 is filled with insulation70. A large diameter pipe 210 is filled with the heat conductivematerial 100, such that the heat conductive material 100 surrounds theone or more upward-flowing pipes 60 and the one or more downward-flowingpipes 80.

As explained earlier herein, this heat conductive material 100 mayharden but does not expand, causing no pressure on the piping system 50or heat exchanging element 40. Once the heat conductive material 100 hasbeen inserted into the well 110 and has hardened around the heatexchange element 40 and piping system 50 in the heat nest 140, it willbegin to heat up until it becomes fully heated and reaches a temperatureof the rock surrounding the heat nest 140 at the bottom 90 of the well110. As the heat conductive material 100 reaches this heat equilibriumtemperature, it exchanges the geothermal heat from the hot rocksurrounding the heat nest 140 to the heat exchanging element 40. Theremaining portion of the well 110 is filled with insulation 70 thatkeeps the heated contents hot as it travels up the well 110 through theone or more upward-flowing pipes 80. This minimizes energy loss so thecontents can be used more efficiently for the generation of power at thetop 180 of the well 110. Accordingly, the heat conductive material 100operates as type of “heating track” which surrounds the heat exchangeelement 40 in the well 110. This heating track maximizes the heat of thecontents and extends the heat exchanging element 40 into the hot rockcreating the heat harnessing component 10.

More specifically, the geothermal heat from the hot rock in the well 110heats the heat conductive material 100 until the system achieves anequilibrium temperature. When the system reaches the equilibriumtemperature, the heat conductive material 100 should be as hot as thehot rock surrounding the heat nest 140. Therefore, as the contents ofthe piping system 50 enters the heat nest 2140 it starts heating upimmediately. When the contents reaches the bottom 90 it is fully heated.As the contents travels back up the heat nest 140 it does not lose heatbecause the heat conductive material 100 has reached the equilibriumtemperature. Use of the heat conductive material 100 within the well 110ensures a system that uniquely maximizes the transport of heat from theheat nest 140 of the well 110 to the top 180. The combination of a heatnest 140 and insulation 70 is especially effective for deep wells wherethe length of the well 110 causes heat loss.

It is to be understood that the equilibrium temperature may differwithin each well and for different contents depending on a variety offactors. For example, the type of rock present within a well may be afactor in determining the depth, size, and materials used inconstructing a heat nest 140 and the type and quality of the heatconductive material 100. The surface area of the rock within the wellinfluences the heat conductivity of the rock, yielding different rangesof temperatures for the equilibrium temperature. The equilibriumtemperature may therefore be a range of temperatures and may varyaccording to the heat needed to be obtained to heat the contents to adesired point.

As an additional feature, the heat conductive material 100 providesadditional stability to the system, minimizing the effects of increasedpressure and increasing the integrity and strength of the heatexchanging element 40. More specifically, as the heat conductivematerial 100 hardens, it provides additional structural support for theheat exchanging element 40, the hardened heat conductive material 100provides structural support for the piping system 50 and the one or moredownward-flowing pipes 60 and the one or more upward-flowing pipes 80that are under pressure. Accordingly, the heat conductive material 100adds to the rigidity of the system. Furthermore, the heat conductivematerial 100 improves the stability of the system by protecting systemcomponents such as the heat exchanging element 40 and the contents ofthe piping system 50 from the caustic environment within the well.

Referring still to FIG. 1, the heated contents flow out of the heatharnessing component 10 and into the electricity generating component20. More specifically, the heated contents flow out of the well 110 andinto a thermal engine 120 positioned at the surface, where the heat fromthe contents is used to generate electricity utilizing techniques wellknown in the art.

FIG. 4 is a flow-chart describing steps in a process for extractinggeothermal heat and generating electricity utilizing the system andmethod of the present invention. A well 110 is drilled and cased viabore hole 190, and the surface area of the rock at a desired depth isincreased in step 300. This step includes determining the appropriatelocation and size for a heat nest 140 once the heat point 130 and bottom90 of the well 110 are estimated. In conjunction with FIGS. 1 and 2, aheat nest 140 is built as in step 310 by inserting a heat exchangingelement 40 having the one or more downward-flowing pipes 60 flowing intoa first side 150 and the one or more upward-flowing pipes 80 flowing outof a second, opposing side 160 is placed into a well 110 at a desireddepth. The starting point of desired depth is the heat point 130 and isdetermined as a function of the desired temperature to which thecontents of the piping system 50 are to be heated, based on the type andsurface area of the surrounding rock. The length of the heat nest 140determines the length of the heat exchanging element 40 and consequentlythe configuration of internal components of the heat exchanging element40.

Once the heat exchanging element 40 and piping system 50 have beeninstalled in the well 110, the heat nest 140 is completely filled withthe heat conductive material 100 from the bottom up as in step 320. Thisis accomplished by injecting the heat conductive material 100 into thewell 110 via the large diameter pipe 210. In an alternate embodiment, athird pipe is inserted into the well 110 to pump the heat conductivematerial 100 into the well 110. The third pipe is then slowly withdrawnfrom the bottom 90 of the well 110 as the heat conductive material 100is pumped into the well 110, until it reaches the heat point 130. Thewell 110 is then filled with insulation 70 from the heat point 130 tothe top 180 of the well 110 as shown in step 330.

Once the heat nest 140 has been completely filled with heat conductivematerial 100 and the third pipe 210 completely withdrawn from the well110, the heat conductive material 100 will begin to harden and heat upin temperature until the equilibrium temperature is reached, therebyconducting geothermal heat from the hot rock surrounding the heat nest140 at the bottom 90 of the well 110 to the heat exchanging element 40as in step 340. Once the heat conductive material 100 reaches theequilibrium temperature, a fluid or gas is pumped into the well 110,through the one or more downward-flowing pipes 60 and into the heatexchanging element 40 as in step 350. This fluid or gas forms thecontents of the piping system 50 and will be geothermally heated withinthe heat exchanging element 40 to form a closed-loop, solid state heatextraction system as in step 360. The contents are then drawn back upfrom the well 110 via the one or more upward-flowing pipes 80.Insulation 70 injected in the well 110 helps to keep the heated contentshot as it travels upward through the well 110, minimizing energy loss sothe heat can be used for the generation of power.

The heated contents then flows out of the well 110 and into theelectricity generating component 20 and the thermal engine 120 at thesurface, where the heat from the contents is used to generateelectricity as in step 370 utilizing techniques well known in the art.

In an alternative embodiment, as discussed above, the system may includemultiple, additional materials used in conjunction with the heatconductive material 100. FIG. 5 illustrates a cross-sectional,conceptual view of a well 110. FIG. 5 illustrates a heat nest 140according to the present invention in which several holes 220 have beendrilled into rock surrounding the heat nest 140 to increase surface areaby filling the several holes 220 with the additional materials. In FIG.5, geothermal heat flows from the cracks and crevices formed in the rockby drilling the several holes 220. The present invention contemplatesthat, prior to building the heat nest 140, the surface area of the rockwill be increased as much as possible to maximize the flow of geothermalheat from the surrounding rock and into the heat exchanging element 40via the heat conductive material 100. Use of additional materials alsoallows more of the fluid to be heated to a desired temperature andtherefore more electricity to be generated.

In another embodiment, the system may include multiple, additional heatexchanging components and/or heat exchanging elements with manydifferent configurations of internal components. Differentconfigurations of the internal components of the heat exchanging element40 are also possible. Increasing the time that contents of the pipingsystem 50 are inside the heat exchanging element 40 increases the amountof fluid or gas that can heated inside the heat nest 140. One suchconfiguration is a helix formation in which the internal components area series of intertwined pipes. Other configurations such as twistedpipes as shown in FIG. 6 exemplify the embodiment in which increasingthe length of pipe (and, therefore, the distance contents must travelwithin heat exchanging element 40) increases the amount of contents thatcan be heated.

It is to be understood that other embodiments may be utilized andstructural and functional changes me be made without departing from thescope of the present invention. The foregoing descriptions of theembodiments of the invention have been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Accordingly, manymodifications and variations are possible in light of the aboveteachings. For example, multiple heat exchanging elements 40 may beimplemented within a heat nest 140. Additionally, any configuration of aheat exchanging element 40 that increases the time contents of thepiping system remain in the heat exchanging element may be utilized.Also, multiple bore holes may be drilled into rock surrounding the heatnest to create more surface area, and such bore holes may be used todrill holes vertically, horizontally, diagonally, or at any angle tocreate more surface area through which geothermal energy may flow. It istherefore intended that the scope of the invention not be limited bythis detailed description.

The invention claimed is:
 1. A heat extraction system for generatinggeothermal heat from within a well, comprising: a heat nest configuredin an area between a heat point determined as a lowest depth whereappropriate heat is encountered in a well and the bottom of a bore holeof the well; multiple bore holes being drilled into rock surrounding theheat nest configured to create more surface area through whichgeothermal energy may flow, the multiple bore holes being drilled inmultiple directions, including drilled vertically, horizontally,diagonally or any angle, in relation to the bore hole of the well andbeing filled with heat conductive material; a heat exchanging elementconfigured with a first side and a second side, and configured in theheat nest at a point between the heat point of the well and the bottomof the bore hole of the well; a piping system configured with adownwardly flowing pipe coupled to the first side of the heat exchangingelement for bringing contents from a surface of the well into the heatnest and configured with an upwardly flowing pipe coupled to the secondside of the heat exchanging element for carrying heated contents to thesurface of the well from the heat nest; and a heat conductive materialinjected into an area within the heat nest near the bottom of the wellbetween the heat exchanging element and rock surrounding the heat nestto form a closed-loop, solid state heat exchange system to heat contentsof the piping system flowing into and out of the heat exchanging elementat an equilibrium temperature at which the rock surrounding the heatnest and generating the geothermal heat continually recoups thegeothermal heat it is conducting to the heat conductive material andabove which the geothermal heat generated by the rock surrounding theheat nest dissipates as the heat conductive material conducts heat fromthe rock surrounding the heat nest to the heat exchanging element, theheat conductive material connecting the rock surrounding the heat nestand the heat exchanging element, the heat conductive materialsolidifying to substantially fill the area within the heat nest totransfer heat from the rock surrounding the heat nest and the heatexchanging element; the closed-loop, solid state heat extraction systemextracting geothermal heat from the well without exposing the rocksurrounding the heat nest to a liquid flow.
 2. The system of claim 1,wherein the equilibrium temperature is increased by increasing thesurface area of the rock surrounding the heat nest.
 3. The system ofclaim 2, wherein the multiple bore holes include cracks or crevicesformed in the rock by drilling the multiple bore holes.
 4. The system ofclaim 3, further comprising at least one additional material injectedinto the multiple bore holes, wherein the at least one additionalmaterial is at least one ball bearing, or at least one bead, or wire, ora meshed metallic material, pipes, or some combination thereof.
 5. Thesystem of claim 2, wherein the surface area of the rock surrounding theheat nest is increased by fracturing the rock surrounding the heat nest.6. The system of claim 1, wherein the piping system includes a set offlexible downward-flowing pipes that carry the contents of the pipingsystem into the heat exchanging element, and a set of flexibleupward-flowing pipes that carry the contents of the piping system out ofthe heat exchanging element.
 7. The system of claim 6, wherein thedownward-flowing pipes and upward-flowing pipes each include a pluralityof layers of wound corrosion resistant steel wiring.
 8. The system ofclaim 1, wherein the contents of the piping system are anenvironmentally inert, heat conductive fluid that does not boil whenheated within the heat nest.
 9. The system of claim 8, wherein thecontents of the piping system are water or gas.
 10. The system of claim1, wherein the heat conductive material is grout.
 11. The system ofclaim 1, wherein the heat conductive material is molten metal.
 12. Thesystem of claim 1, wherein the heat conductive material is a ceramic.13. The system of claim 1, wherein the heat conductive material is amesh material.
 14. The system of claim 1, wherein the heat conductivematerial is plastic.
 15. The system of claim 1, wherein the heatconductive material stabilizes pressure on the piping system and theheat exchanging element within the heat nest.
 16. The system of claim 1,wherein the equilibrium temperature is a range of temperaturesdetermined at least in part by a surface area of the rock within theheat nest.
 17. The system of claim 1, wherein the heat exchangingelement has a helix shape, and the piping system within the heatexchanging element comprises at least one twisted pipe to increase thedistance contents of the piping system flows within the heat exchangingelement.
 18. The system according to claim 1, wherein the system furthercomprises: an electricity generating component including a thermalengine and being configured to receive the heated contents from thepiping system and produce electricity using the heated contents.
 19. Thesystem according to claim 18, wherein the piping system comprises a setof downward-flowing pipes and a set of upward-flowing pipes, theupward-flowing pipes conveying contents of the piping system heated bythe heat exchanging element to the surface of the well and into theelectricity generating component.
 20. The system according to claim 1,wherein the system comprises insulation configured to fill the rest ofthe bore hole of the well between a wall of the bore hole and at leastsome part of the piping system, including where the insulation isinserted into the well and substantially surrounding at least theupward-flowing pipe at at least one position between the heat nest andthe surface of the well to maintain a temperature of the contents of thepiping system substantially constant as the contents of the pipingsystem are pumped to the surface of the well.
 21. The system of claim19, wherein the downward-flowing pipes are flexible, or theupward-flowing pipes are flexible, or some combination thereof.
 22. Thesystem of claim 1, wherein the heat conductive material is injected intothe heat nest via a pipe inserted through the bore hole and withdrawnonce the heat nest has been filled with the heat conductive material.23. The system of claim 1, wherein the multiple bore holes are filledwith at least one additional material configured to increase the surfacearea of conduction, so that geothermal heat conducted from the rocksurrounding the heat nest is released over greater surface areasprovided by the introduction of the at least one additional materialinto the heat nest.
 24. The system of claim 23, wherein the heatconductive material bonds with the at least one additional material andsolidifies around the at least one additional material.
 25. The systemof claim 1, wherein the heat exchanging element is a cross-flow heatexchanger configured so that heat flows perpendicular to the fluid whichneeds to be heated, such that the heat flow passes over/around thecross-flow heat exchanger in a perpendicular direction, so as to heatthe fluid which flows through a direction perpendicular to the heatflow.
 26. The system of claim 25, wherein the cross-flow heat exchangeris a high temperature heat exchanger comprised of a recuperative type“cross flow” heat exchanger, in which fluids heat on either side of adividing wall.
 27. The system of claim 25, wherein the cross-flow heatexchanger is comprises a high temperature heat exchanger (HTHE) whichutilizes a regenerative or evaporative design.
 28. The system of claim1, wherein the heat conductive material is copper.
 29. A method ofextracting geothermal heat from within a drilled well, comprising:determining a type of rock at a depth of a well, a surface area of therock at the depth of a well, and a heat conductivity factor of the rockat the depth of the well; increasing the surface area of the rock at adesired point in the well between a heat point of the well and a bottomof the well; forming a heat nest within the well beginning at the bottomof the well and ending at the heat point of the well; drilling multiplebore holes into rock surrounding the heat nest configured to create moresurface area through which geothermal energy may flow, the multiple boreholes being drilled in multiple directions, including drilledvertically, horizontally, diagonally or any angle, in relation to thebore hole of the well and being filled with heat conductive material;injecting a heat conductive material between rock surrounding the heatnest and a heat exchanging element having a first side and a second sidewithin the heat nest to form a closed-loop, solid-state heat extractionsystem to exchange heat from the rock surrounding the heat nest to theheat exchanging element to heat contents of a piping system flowing froma downwardly flowing pipe into the first side of the heat exchangingelement and flowing from the second side of the heat exchanging elementinto an upwardly flowing pipe at an equilibrium temperature at which therock surrounding the heat nest and generating the geothermal heatcontinually recoups the geothermal heat it is exchanging with the heatconductive material and above which the geothermal heat generated by therock surrounding the heat nest dissipates as the heat conductivematerial exchanges heat from the rock surrounding the heat nest to theheat exchanging element; and insulating the piping system between theheat nest and a surface of the well, the closed-loop solid state heatextraction system extracting geothermal heat from the well withoutexposing the rock surrounding the heat nest to a liquid flow.
 30. Themethod of claim 29, wherein the increasing the surface area of the rocksurrounding the heat nest increases the equilibrium temperature.
 31. Themethod of claim 30, wherein the method comprises configuring themultiple bore holes with cracks or crevices formed in the rock bydrilling the multiple bore holes for further increasing the surface areaof the rock.
 32. The method of claim 31, further comprising injecting atleast one additional material in the multiple bore holes, wherein the atleast one additional material is at least one ball bearing, or at leastone bead, or wire, or a meshed metallic material, or pipes, or somecombination thereof.
 33. The method of claim 29, wherein the contents ofthe piping system are an environmentally inert, heat conductive fluidthat does not boil when heated within the heat nest.
 34. The method ofclaim 33, wherein the contents of the piping system are water or a gas.35. The method of claim 29, wherein the heat conductive material isgrout, or a molten metal such as copper, or a ceramic, or a meshmaterial, or a plastic, or some combination thereof.
 36. The method ofclaim 29, wherein the injecting a heat conductive material into the wellfurther comprises inserting a pipe through a bore hole and withdrawingthe pipe once the heat nest has been filled with the heat conductivematerial.
 37. The method of claim 29, wherein the insulating the pipingsystem further comprises insulating the piping system at at least onepoint between the heat nest and surface of the well.
 38. The method ofclaim 29, wherein the equilibrium temperature is a range oftemperatures.
 39. The method of claim 29, wherein the extractinggeothermal heat further comprises forming a shape of the heat exchangingelement into a helix, in which the piping system within the heatexchanging element comprises at least one twisted pipe to increase adistance contents of the piping system flows within the heat exchangingelement.
 40. The method of claim 30, wherein the increasing a surfacearea of the rock surrounding the heat nest to increase the equilibriumtemperature further comprises fracturing the surface area of the rocksurrounding the heat nest.
 41. The method of claim 29, wherein thedownward-flowing pipe and upward-flowing pipe each include a pluralityof layers of wound corrosion resistant steel wiring.
 42. The method ofclaim 29, wherein the method comprises filing the multiple bore holeswith at least one additional material configured to increase the surfacearea of conduction, so that geothermal heat conducted from the rocksurrounding the heat nest is released over greater surface areas provideby the introduction of the at least one additional material into theheat nest.
 43. The method of claim 42, wherein the method comprisesbonding the heat conductive material with the at least one additionalmaterial and solidifying the heat conductive material around the atleast one additional material.
 44. The method of claim 29, wherein themethod configuring the heat exchanger as a cross-flow heat exchanger sothat heat flows perpendicular to the fluid which needs to be heated,such that the heat flow passes over/around the exchanger in aperpendicular direction, so as to heat the fluid which flows through adirection perpendicular to the heat flow.
 45. The method of claim 44,wherein the method configuring the cross-flow heat exchanger as a hightemperature heat exchanger comprised of a recuperative type “cross flow”heat exchanger, in which fluids heat on either side of a dividing wall.46. The system of claim 44, wherein the cross-flow heat exchanger isconfigured with two sides, with fluid flowing in one side heating fluidflowing in another side.
 47. A heat extraction system for generatinggeothermal heat from within a drilled well, comprising: a heat nest neara bottom of the drilled well; a heat exchanging element configured witha first side, a second side and a plurality of capillaries; a pipingsystem configured with one or more downwardly flowing pipes for bringingthe contents of the piping system from a surface of the well into thefirst side of the heat exchanging element in the heat nest andconfigured with one or more upwardly flowing pipes for carrying heatedcontents from a second side of the heat exchanging element to thesurface of the well from the heat nest; a heat conductive materialinjected into an area within the heat nest between the heat exchangingelement and rock surrounding the heat nest, wherein the heat conductivematerial solidifies to substantially fill the area within the heat nestto transfer heat from the rock surrounding the heat nest and the heatexchanging element to form a closed-loop, solid state heat exchangesystem to heat contents of the piping system flowing into and out of theheat exchanging element at an equilibrium temperature at which the rocksurrounding the heat nest and generating the geothermal heat continuallyrecoups the geothermal heat it is conducting to the heat conductivematerial and above which the geothermal heat generated by the rocksurrounding the heat nest dissipates as the heat conductive materialconducts heat from the rock surrounding the heat nest to the heatexchanging element; and wherein the closed-loop solid state heatextraction system extracts geothermal heat from the well withoutexposing the rock surrounding the heat nest to a liquid flow.
 48. Thesystem of claim 47, wherein the contents of the downward-flowing pipesare dispersed through the plurality of capillaries after entering theheat exchanging element.
 49. A method of extracting geothermal heat fromwithin a drilled well, comprising: determining a type of rock at a depthof a well, a surface area of the rock at the depth of the well, and aheat conductivity factor of the rock at the depth of the well;increasing the surface area of the rock at a desired point in the wellbetween a heat point of the well and a bottom of the well; forming aheat nest within the well beginning at the bottom of the well and endingat the heat point of the well; injecting a heat conductive materialbetween rock surrounding the heat nest and a heat exchanging elementwithin the heat nest to form a closed-loop, solid-state heat extractionsystem to exchange heat from the rock surrounding the heat nest to theheat exchanging element to heat contents of a piping system flowing intoand out of the heat exchanging element at an equilibrium temperature atwhich the rock surrounding the heat nest and generating the geothermalheat continually recoups the geothermal heat it is exchanging with theheat conductive material and above which the geothermal heat generatedby the rock surrounding the heat nest dissipates as the heat conductivematerial exchanges heat from the rock surrounding the heat nest to theheat exchanging element; insulating the piping system between the heatnest and a surface of the well, pumping the contents of the pipingsystem into a first side of the heat exchanging element in a set offlexible, downward-flowing pipes and out a second side of the heatexchanging element in a set of flexible, upward- flowing pipes; anddispersing the contents of the piping system into a plurality ofcapillaries coupled to the piping system within the heat nest; whereinthe closed-loop solid state heat extraction system extracts geothermalheat from the well without exposing the rock surrounding the heat nestto a liquid flow.
 50. The method of claim 49, wherein each capillary inthe plurality of capillaries has a diameter smaller than a diameter of adownward-flowing pipe of the piping system, thereby allowing thecontents of the piping system to heat quickly as the contents passthrough the plurality of capillaries.